Building block toys are sometimes sorted with sieves that rely upon sizes or shapes of toys. Most of the time block toys are sorted by eye, but oftentimes pieces from one set of toys resemble pieces from another set.
Parents of young children who play with different sets of building block toys, assembling various creations, are faced with the task of putting the toys away when the creations are disassembled, frequently all at the same time. A favorite toy of young children is Lego block toys. Lego is a registered trademark of Interlego AG. This kind of toy is marketed in many different sets, but the pieces that comprise each set are frequently similar or identical to pieces in other sets. Besides the similar pieces, each set frequently possesses unique pieces. It is critical to identify and segregate the unique pieces, so that the toy can be reassembled in the future. Yet, there is no convenient way to identify pieces of the same toy set when multiple toy sets are disassembled. An object of the invention is to provide a simple way of segregating pieces of building block toy sets so that different sets of building block toys, particularly Legos, can be reassembled.
In U.S. Pat. No. 4,013,490 F. Ryan and R. Miller describe tagging explosives with different inorganic phosphors and other materials for identifying particular explosives by unique luminescence. U.S. Pat. No. 3,231,738 describes tagging explosives with organic dye particles for a similar purpose.